1 /*
2 * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 *
6 * Author: Pawel Osciak <pawel@osciak.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation.
11 */
12
13 #include <linux/dma-buf.h>
14 #include <linux/module.h>
15 #include <linux/scatterlist.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/dma-mapping.h>
19
20 #include <media/videobuf2-core.h>
21 #include <media/videobuf2-dma-contig.h>
22 #include <media/videobuf2-memops.h>
23
24 struct vb2_dc_conf {
25 struct device *dev;
26 };
27
28 struct vb2_dc_buf {
29 struct device *dev;
30 void *vaddr;
31 unsigned long size;
32 dma_addr_t dma_addr;
33 enum dma_data_direction dma_dir;
34 struct sg_table *dma_sgt;
35
36 /* MMAP related */
37 struct vb2_vmarea_handler handler;
38 atomic_t refcount;
39 struct sg_table *sgt_base;
40
41 /* USERPTR related */
42 struct vm_area_struct *vma;
43
44 /* DMABUF related */
45 struct dma_buf_attachment *db_attach;
46 };
47
48 /*********************************************/
49 /* scatterlist table functions */
50 /*********************************************/
51
52
vb2_dc_sgt_foreach_page(struct sg_table * sgt,void (* cb)(struct page * pg))53 static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
54 void (*cb)(struct page *pg))
55 {
56 struct scatterlist *s;
57 unsigned int i;
58
59 for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
60 struct page *page = sg_page(s);
61 unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
62 >> PAGE_SHIFT;
63 unsigned int j;
64
65 for (j = 0; j < n_pages; ++j, ++page)
66 cb(page);
67 }
68 }
69
vb2_dc_get_contiguous_size(struct sg_table * sgt)70 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
71 {
72 struct scatterlist *s;
73 dma_addr_t expected = sg_dma_address(sgt->sgl);
74 unsigned int i;
75 unsigned long size = 0;
76
77 for_each_sg(sgt->sgl, s, sgt->nents, i) {
78 if (sg_dma_address(s) != expected)
79 break;
80 expected = sg_dma_address(s) + sg_dma_len(s);
81 size += sg_dma_len(s);
82 }
83 return size;
84 }
85
86 /*********************************************/
87 /* callbacks for all buffers */
88 /*********************************************/
89
vb2_dc_cookie(void * buf_priv)90 static void *vb2_dc_cookie(void *buf_priv)
91 {
92 struct vb2_dc_buf *buf = buf_priv;
93
94 return &buf->dma_addr;
95 }
96
vb2_dc_vaddr(void * buf_priv)97 static void *vb2_dc_vaddr(void *buf_priv)
98 {
99 struct vb2_dc_buf *buf = buf_priv;
100
101 if (!buf->vaddr && buf->db_attach)
102 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
103
104 return buf->vaddr;
105 }
106
vb2_dc_num_users(void * buf_priv)107 static unsigned int vb2_dc_num_users(void *buf_priv)
108 {
109 struct vb2_dc_buf *buf = buf_priv;
110
111 return atomic_read(&buf->refcount);
112 }
113
vb2_dc_prepare(void * buf_priv)114 static void vb2_dc_prepare(void *buf_priv)
115 {
116 struct vb2_dc_buf *buf = buf_priv;
117 struct sg_table *sgt = buf->dma_sgt;
118
119 /* DMABUF exporter will flush the cache for us */
120 if (!sgt || buf->db_attach)
121 return;
122
123 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
124 }
125
vb2_dc_finish(void * buf_priv)126 static void vb2_dc_finish(void *buf_priv)
127 {
128 struct vb2_dc_buf *buf = buf_priv;
129 struct sg_table *sgt = buf->dma_sgt;
130
131 /* DMABUF exporter will flush the cache for us */
132 if (!sgt || buf->db_attach)
133 return;
134
135 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
136 }
137
138 /*********************************************/
139 /* callbacks for MMAP buffers */
140 /*********************************************/
141
vb2_dc_put(void * buf_priv)142 static void vb2_dc_put(void *buf_priv)
143 {
144 struct vb2_dc_buf *buf = buf_priv;
145
146 if (!atomic_dec_and_test(&buf->refcount))
147 return;
148
149 if (buf->sgt_base) {
150 sg_free_table(buf->sgt_base);
151 kfree(buf->sgt_base);
152 }
153 dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
154 put_device(buf->dev);
155 kfree(buf);
156 }
157
vb2_dc_alloc(void * alloc_ctx,unsigned long size,gfp_t gfp_flags)158 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
159 {
160 struct vb2_dc_conf *conf = alloc_ctx;
161 struct device *dev = conf->dev;
162 struct vb2_dc_buf *buf;
163
164 buf = kzalloc(sizeof *buf, GFP_KERNEL);
165 if (!buf)
166 return ERR_PTR(-ENOMEM);
167
168 buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr,
169 GFP_KERNEL | gfp_flags);
170 if (!buf->vaddr) {
171 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
172 kfree(buf);
173 return ERR_PTR(-ENOMEM);
174 }
175
176 /* Prevent the device from being released while the buffer is used */
177 buf->dev = get_device(dev);
178 buf->size = size;
179
180 buf->handler.refcount = &buf->refcount;
181 buf->handler.put = vb2_dc_put;
182 buf->handler.arg = buf;
183
184 atomic_inc(&buf->refcount);
185
186 return buf;
187 }
188
vb2_dc_mmap(void * buf_priv,struct vm_area_struct * vma)189 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
190 {
191 struct vb2_dc_buf *buf = buf_priv;
192 int ret;
193
194 if (!buf) {
195 printk(KERN_ERR "No buffer to map\n");
196 return -EINVAL;
197 }
198
199 /*
200 * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
201 * map whole buffer
202 */
203 vma->vm_pgoff = 0;
204
205 ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
206 buf->dma_addr, buf->size);
207
208 if (ret) {
209 pr_err("Remapping memory failed, error: %d\n", ret);
210 return ret;
211 }
212
213 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
214 vma->vm_private_data = &buf->handler;
215 vma->vm_ops = &vb2_common_vm_ops;
216
217 vma->vm_ops->open(vma);
218
219 pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
220 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
221 buf->size);
222
223 return 0;
224 }
225
226 /*********************************************/
227 /* DMABUF ops for exporters */
228 /*********************************************/
229
230 struct vb2_dc_attachment {
231 struct sg_table sgt;
232 enum dma_data_direction dir;
233 };
234
vb2_dc_dmabuf_ops_attach(struct dma_buf * dbuf,struct device * dev,struct dma_buf_attachment * dbuf_attach)235 static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
236 struct dma_buf_attachment *dbuf_attach)
237 {
238 struct vb2_dc_attachment *attach;
239 unsigned int i;
240 struct scatterlist *rd, *wr;
241 struct sg_table *sgt;
242 struct vb2_dc_buf *buf = dbuf->priv;
243 int ret;
244
245 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
246 if (!attach)
247 return -ENOMEM;
248
249 sgt = &attach->sgt;
250 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
251 * map the same scatter list to multiple attachments at the same time.
252 */
253 ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
254 if (ret) {
255 kfree(attach);
256 return -ENOMEM;
257 }
258
259 rd = buf->sgt_base->sgl;
260 wr = sgt->sgl;
261 for (i = 0; i < sgt->orig_nents; ++i) {
262 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
263 rd = sg_next(rd);
264 wr = sg_next(wr);
265 }
266
267 attach->dir = DMA_NONE;
268 dbuf_attach->priv = attach;
269
270 return 0;
271 }
272
vb2_dc_dmabuf_ops_detach(struct dma_buf * dbuf,struct dma_buf_attachment * db_attach)273 static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
274 struct dma_buf_attachment *db_attach)
275 {
276 struct vb2_dc_attachment *attach = db_attach->priv;
277 struct sg_table *sgt;
278
279 if (!attach)
280 return;
281
282 sgt = &attach->sgt;
283
284 /* release the scatterlist cache */
285 if (attach->dir != DMA_NONE)
286 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
287 attach->dir);
288 sg_free_table(sgt);
289 kfree(attach);
290 db_attach->priv = NULL;
291 }
292
vb2_dc_dmabuf_ops_map(struct dma_buf_attachment * db_attach,enum dma_data_direction dir)293 static struct sg_table *vb2_dc_dmabuf_ops_map(
294 struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
295 {
296 struct vb2_dc_attachment *attach = db_attach->priv;
297 /* stealing dmabuf mutex to serialize map/unmap operations */
298 struct mutex *lock = &db_attach->dmabuf->lock;
299 struct sg_table *sgt;
300 int ret;
301
302 mutex_lock(lock);
303
304 sgt = &attach->sgt;
305 /* return previously mapped sg table */
306 if (attach->dir == dir) {
307 mutex_unlock(lock);
308 return sgt;
309 }
310
311 /* release any previous cache */
312 if (attach->dir != DMA_NONE) {
313 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
314 attach->dir);
315 attach->dir = DMA_NONE;
316 }
317
318 /* mapping to the client with new direction */
319 ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
320 if (ret <= 0) {
321 pr_err("failed to map scatterlist\n");
322 mutex_unlock(lock);
323 return ERR_PTR(-EIO);
324 }
325
326 attach->dir = dir;
327
328 mutex_unlock(lock);
329
330 return sgt;
331 }
332
vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment * db_attach,struct sg_table * sgt,enum dma_data_direction dir)333 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
334 struct sg_table *sgt, enum dma_data_direction dir)
335 {
336 /* nothing to be done here */
337 }
338
vb2_dc_dmabuf_ops_release(struct dma_buf * dbuf)339 static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
340 {
341 /* drop reference obtained in vb2_dc_get_dmabuf */
342 vb2_dc_put(dbuf->priv);
343 }
344
vb2_dc_dmabuf_ops_kmap(struct dma_buf * dbuf,unsigned long pgnum)345 static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
346 {
347 struct vb2_dc_buf *buf = dbuf->priv;
348
349 return buf->vaddr + pgnum * PAGE_SIZE;
350 }
351
vb2_dc_dmabuf_ops_vmap(struct dma_buf * dbuf)352 static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
353 {
354 struct vb2_dc_buf *buf = dbuf->priv;
355
356 return buf->vaddr;
357 }
358
vb2_dc_dmabuf_ops_mmap(struct dma_buf * dbuf,struct vm_area_struct * vma)359 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
360 struct vm_area_struct *vma)
361 {
362 return vb2_dc_mmap(dbuf->priv, vma);
363 }
364
365 static struct dma_buf_ops vb2_dc_dmabuf_ops = {
366 .attach = vb2_dc_dmabuf_ops_attach,
367 .detach = vb2_dc_dmabuf_ops_detach,
368 .map_dma_buf = vb2_dc_dmabuf_ops_map,
369 .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
370 .kmap = vb2_dc_dmabuf_ops_kmap,
371 .kmap_atomic = vb2_dc_dmabuf_ops_kmap,
372 .vmap = vb2_dc_dmabuf_ops_vmap,
373 .mmap = vb2_dc_dmabuf_ops_mmap,
374 .release = vb2_dc_dmabuf_ops_release,
375 };
376
vb2_dc_get_base_sgt(struct vb2_dc_buf * buf)377 static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
378 {
379 int ret;
380 struct sg_table *sgt;
381
382 sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
383 if (!sgt) {
384 dev_err(buf->dev, "failed to alloc sg table\n");
385 return NULL;
386 }
387
388 ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
389 buf->size);
390 if (ret < 0) {
391 dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
392 kfree(sgt);
393 return NULL;
394 }
395
396 return sgt;
397 }
398
vb2_dc_get_dmabuf(void * buf_priv,unsigned long flags)399 static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
400 {
401 struct vb2_dc_buf *buf = buf_priv;
402 struct dma_buf *dbuf;
403
404 if (!buf->sgt_base)
405 buf->sgt_base = vb2_dc_get_base_sgt(buf);
406
407 if (WARN_ON(!buf->sgt_base))
408 return NULL;
409
410 dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, flags, NULL);
411 if (IS_ERR(dbuf))
412 return NULL;
413
414 /* dmabuf keeps reference to vb2 buffer */
415 atomic_inc(&buf->refcount);
416
417 return dbuf;
418 }
419
420 /*********************************************/
421 /* callbacks for USERPTR buffers */
422 /*********************************************/
423
vma_is_io(struct vm_area_struct * vma)424 static inline int vma_is_io(struct vm_area_struct *vma)
425 {
426 return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
427 }
428
vb2_dc_get_user_pfn(unsigned long start,int n_pages,struct vm_area_struct * vma,unsigned long * res)429 static int vb2_dc_get_user_pfn(unsigned long start, int n_pages,
430 struct vm_area_struct *vma, unsigned long *res)
431 {
432 unsigned long pfn, start_pfn, prev_pfn;
433 unsigned int i;
434 int ret;
435
436 if (!vma_is_io(vma))
437 return -EFAULT;
438
439 ret = follow_pfn(vma, start, &pfn);
440 if (ret)
441 return ret;
442
443 start_pfn = pfn;
444 start += PAGE_SIZE;
445
446 for (i = 1; i < n_pages; ++i, start += PAGE_SIZE) {
447 prev_pfn = pfn;
448 ret = follow_pfn(vma, start, &pfn);
449
450 if (ret) {
451 pr_err("no page for address %lu\n", start);
452 return ret;
453 }
454 if (pfn != prev_pfn + 1)
455 return -EINVAL;
456 }
457
458 *res = start_pfn;
459 return 0;
460 }
461
vb2_dc_get_user_pages(unsigned long start,struct page ** pages,int n_pages,struct vm_area_struct * vma,int write)462 static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
463 int n_pages, struct vm_area_struct *vma, int write)
464 {
465 if (vma_is_io(vma)) {
466 unsigned int i;
467
468 for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
469 unsigned long pfn;
470 int ret = follow_pfn(vma, start, &pfn);
471
472 if (!pfn_valid(pfn))
473 return -EINVAL;
474
475 if (ret) {
476 pr_err("no page for address %lu\n", start);
477 return ret;
478 }
479 pages[i] = pfn_to_page(pfn);
480 }
481 } else {
482 int n;
483
484 n = get_user_pages(current, current->mm, start & PAGE_MASK,
485 n_pages, write, 1, pages, NULL);
486 /* negative error means that no page was pinned */
487 n = max(n, 0);
488 if (n != n_pages) {
489 pr_err("got only %d of %d user pages\n", n, n_pages);
490 while (n)
491 put_page(pages[--n]);
492 return -EFAULT;
493 }
494 }
495
496 return 0;
497 }
498
vb2_dc_put_dirty_page(struct page * page)499 static void vb2_dc_put_dirty_page(struct page *page)
500 {
501 set_page_dirty_lock(page);
502 put_page(page);
503 }
504
vb2_dc_put_userptr(void * buf_priv)505 static void vb2_dc_put_userptr(void *buf_priv)
506 {
507 struct vb2_dc_buf *buf = buf_priv;
508 struct sg_table *sgt = buf->dma_sgt;
509
510 if (sgt) {
511 dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
512 if (!vma_is_io(buf->vma))
513 vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
514
515 sg_free_table(sgt);
516 kfree(sgt);
517 }
518 vb2_put_vma(buf->vma);
519 kfree(buf);
520 }
521
522 /*
523 * For some kind of reserved memory there might be no struct page available,
524 * so all that can be done to support such 'pages' is to try to convert
525 * pfn to dma address or at the last resort just assume that
526 * dma address == physical address (like it has been assumed in earlier version
527 * of videobuf2-dma-contig
528 */
529
530 #ifdef __arch_pfn_to_dma
vb2_dc_pfn_to_dma(struct device * dev,unsigned long pfn)531 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
532 {
533 return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
534 }
535 #elif defined(__pfn_to_bus)
vb2_dc_pfn_to_dma(struct device * dev,unsigned long pfn)536 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
537 {
538 return (dma_addr_t)__pfn_to_bus(pfn);
539 }
540 #elif defined(__pfn_to_phys)
vb2_dc_pfn_to_dma(struct device * dev,unsigned long pfn)541 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
542 {
543 return (dma_addr_t)__pfn_to_phys(pfn);
544 }
545 #else
vb2_dc_pfn_to_dma(struct device * dev,unsigned long pfn)546 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
547 {
548 /* really, we cannot do anything better at this point */
549 return (dma_addr_t)(pfn) << PAGE_SHIFT;
550 }
551 #endif
552
vb2_dc_get_userptr(void * alloc_ctx,unsigned long vaddr,unsigned long size,int write)553 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
554 unsigned long size, int write)
555 {
556 struct vb2_dc_conf *conf = alloc_ctx;
557 struct vb2_dc_buf *buf;
558 unsigned long start;
559 unsigned long end;
560 unsigned long offset;
561 struct page **pages;
562 int n_pages;
563 int ret = 0;
564 struct vm_area_struct *vma;
565 struct sg_table *sgt;
566 unsigned long contig_size;
567 unsigned long dma_align = dma_get_cache_alignment();
568
569 /* Only cache aligned DMA transfers are reliable */
570 if (!IS_ALIGNED(vaddr | size, dma_align)) {
571 pr_debug("user data must be aligned to %lu bytes\n", dma_align);
572 return ERR_PTR(-EINVAL);
573 }
574
575 if (!size) {
576 pr_debug("size is zero\n");
577 return ERR_PTR(-EINVAL);
578 }
579
580 buf = kzalloc(sizeof *buf, GFP_KERNEL);
581 if (!buf)
582 return ERR_PTR(-ENOMEM);
583
584 buf->dev = conf->dev;
585 buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
586
587 start = vaddr & PAGE_MASK;
588 offset = vaddr & ~PAGE_MASK;
589 end = PAGE_ALIGN(vaddr + size);
590 n_pages = (end - start) >> PAGE_SHIFT;
591
592 pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
593 if (!pages) {
594 ret = -ENOMEM;
595 pr_err("failed to allocate pages table\n");
596 goto fail_buf;
597 }
598
599 /* current->mm->mmap_sem is taken by videobuf2 core */
600 vma = find_vma(current->mm, vaddr);
601 if (!vma) {
602 pr_err("no vma for address %lu\n", vaddr);
603 ret = -EFAULT;
604 goto fail_pages;
605 }
606
607 if (vma->vm_end < vaddr + size) {
608 pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
609 ret = -EFAULT;
610 goto fail_pages;
611 }
612
613 buf->vma = vb2_get_vma(vma);
614 if (!buf->vma) {
615 pr_err("failed to copy vma\n");
616 ret = -ENOMEM;
617 goto fail_pages;
618 }
619
620 /* extract page list from userspace mapping */
621 ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
622 if (ret) {
623 unsigned long pfn;
624 if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {
625 buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn);
626 buf->size = size;
627 kfree(pages);
628 return buf;
629 }
630
631 pr_err("failed to get user pages\n");
632 goto fail_vma;
633 }
634
635 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
636 if (!sgt) {
637 pr_err("failed to allocate sg table\n");
638 ret = -ENOMEM;
639 goto fail_get_user_pages;
640 }
641
642 ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
643 offset, size, GFP_KERNEL);
644 if (ret) {
645 pr_err("failed to initialize sg table\n");
646 goto fail_sgt;
647 }
648
649 /* pages are no longer needed */
650 kfree(pages);
651 pages = NULL;
652
653 sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
654 buf->dma_dir);
655 if (sgt->nents <= 0) {
656 pr_err("failed to map scatterlist\n");
657 ret = -EIO;
658 goto fail_sgt_init;
659 }
660
661 contig_size = vb2_dc_get_contiguous_size(sgt);
662 if (contig_size < size) {
663 pr_err("contiguous mapping is too small %lu/%lu\n",
664 contig_size, size);
665 ret = -EFAULT;
666 goto fail_map_sg;
667 }
668
669 buf->dma_addr = sg_dma_address(sgt->sgl);
670 buf->size = size;
671 buf->dma_sgt = sgt;
672
673 return buf;
674
675 fail_map_sg:
676 dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
677
678 fail_sgt_init:
679 if (!vma_is_io(buf->vma))
680 vb2_dc_sgt_foreach_page(sgt, put_page);
681 sg_free_table(sgt);
682
683 fail_sgt:
684 kfree(sgt);
685
686 fail_get_user_pages:
687 if (pages && !vma_is_io(buf->vma))
688 while (n_pages)
689 put_page(pages[--n_pages]);
690
691 fail_vma:
692 vb2_put_vma(buf->vma);
693
694 fail_pages:
695 kfree(pages); /* kfree is NULL-proof */
696
697 fail_buf:
698 kfree(buf);
699
700 return ERR_PTR(ret);
701 }
702
703 /*********************************************/
704 /* callbacks for DMABUF buffers */
705 /*********************************************/
706
vb2_dc_map_dmabuf(void * mem_priv)707 static int vb2_dc_map_dmabuf(void *mem_priv)
708 {
709 struct vb2_dc_buf *buf = mem_priv;
710 struct sg_table *sgt;
711 unsigned long contig_size;
712
713 if (WARN_ON(!buf->db_attach)) {
714 pr_err("trying to pin a non attached buffer\n");
715 return -EINVAL;
716 }
717
718 if (WARN_ON(buf->dma_sgt)) {
719 pr_err("dmabuf buffer is already pinned\n");
720 return 0;
721 }
722
723 /* get the associated scatterlist for this buffer */
724 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
725 if (IS_ERR(sgt)) {
726 pr_err("Error getting dmabuf scatterlist\n");
727 return -EINVAL;
728 }
729
730 /* checking if dmabuf is big enough to store contiguous chunk */
731 contig_size = vb2_dc_get_contiguous_size(sgt);
732 if (contig_size < buf->size) {
733 pr_err("contiguous chunk is too small %lu/%lu b\n",
734 contig_size, buf->size);
735 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
736 return -EFAULT;
737 }
738
739 buf->dma_addr = sg_dma_address(sgt->sgl);
740 buf->dma_sgt = sgt;
741 buf->vaddr = NULL;
742
743 return 0;
744 }
745
vb2_dc_unmap_dmabuf(void * mem_priv)746 static void vb2_dc_unmap_dmabuf(void *mem_priv)
747 {
748 struct vb2_dc_buf *buf = mem_priv;
749 struct sg_table *sgt = buf->dma_sgt;
750
751 if (WARN_ON(!buf->db_attach)) {
752 pr_err("trying to unpin a not attached buffer\n");
753 return;
754 }
755
756 if (WARN_ON(!sgt)) {
757 pr_err("dmabuf buffer is already unpinned\n");
758 return;
759 }
760
761 if (buf->vaddr) {
762 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
763 buf->vaddr = NULL;
764 }
765 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
766
767 buf->dma_addr = 0;
768 buf->dma_sgt = NULL;
769 }
770
vb2_dc_detach_dmabuf(void * mem_priv)771 static void vb2_dc_detach_dmabuf(void *mem_priv)
772 {
773 struct vb2_dc_buf *buf = mem_priv;
774
775 /* if vb2 works correctly you should never detach mapped buffer */
776 if (WARN_ON(buf->dma_addr))
777 vb2_dc_unmap_dmabuf(buf);
778
779 /* detach this attachment */
780 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
781 kfree(buf);
782 }
783
vb2_dc_attach_dmabuf(void * alloc_ctx,struct dma_buf * dbuf,unsigned long size,int write)784 static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
785 unsigned long size, int write)
786 {
787 struct vb2_dc_conf *conf = alloc_ctx;
788 struct vb2_dc_buf *buf;
789 struct dma_buf_attachment *dba;
790
791 if (dbuf->size < size)
792 return ERR_PTR(-EFAULT);
793
794 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
795 if (!buf)
796 return ERR_PTR(-ENOMEM);
797
798 buf->dev = conf->dev;
799 /* create attachment for the dmabuf with the user device */
800 dba = dma_buf_attach(dbuf, buf->dev);
801 if (IS_ERR(dba)) {
802 pr_err("failed to attach dmabuf\n");
803 kfree(buf);
804 return dba;
805 }
806
807 buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
808 buf->size = size;
809 buf->db_attach = dba;
810
811 return buf;
812 }
813
814 /*********************************************/
815 /* DMA CONTIG exported functions */
816 /*********************************************/
817
818 const struct vb2_mem_ops vb2_dma_contig_memops = {
819 .alloc = vb2_dc_alloc,
820 .put = vb2_dc_put,
821 .get_dmabuf = vb2_dc_get_dmabuf,
822 .cookie = vb2_dc_cookie,
823 .vaddr = vb2_dc_vaddr,
824 .mmap = vb2_dc_mmap,
825 .get_userptr = vb2_dc_get_userptr,
826 .put_userptr = vb2_dc_put_userptr,
827 .prepare = vb2_dc_prepare,
828 .finish = vb2_dc_finish,
829 .map_dmabuf = vb2_dc_map_dmabuf,
830 .unmap_dmabuf = vb2_dc_unmap_dmabuf,
831 .attach_dmabuf = vb2_dc_attach_dmabuf,
832 .detach_dmabuf = vb2_dc_detach_dmabuf,
833 .num_users = vb2_dc_num_users,
834 };
835 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
836
vb2_dma_contig_init_ctx(struct device * dev)837 void *vb2_dma_contig_init_ctx(struct device *dev)
838 {
839 struct vb2_dc_conf *conf;
840
841 conf = kzalloc(sizeof *conf, GFP_KERNEL);
842 if (!conf)
843 return ERR_PTR(-ENOMEM);
844
845 conf->dev = dev;
846
847 return conf;
848 }
849 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
850
vb2_dma_contig_cleanup_ctx(void * alloc_ctx)851 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
852 {
853 kfree(alloc_ctx);
854 }
855 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
856
857 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
858 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
859 MODULE_LICENSE("GPL");
860